Judge a book by its cover, and lost son feather（以貌取人,失之子羽）
故事内容翻译：
During the spring and autumn, the great educationalist Confucius has many students, and there is a JiaoZi feather, a call to the slaughter. The son because grow very ugly plume, so Confucius to his attitude is very cold, and then the son feather had to leave school, studying back to their knowledge. And because grow instrument to kill him, and eloquent, so Confucius like him very much, think this the students must be very have ambition.
However, things are not Confucius's unexpected, the son is a love of learning plume and independent thinking, he left after Confucius more strenuously study, study diligently, has become a very famous scholars. Many young so and he traveled to study door, his reputation in the spread between governors. Instead, to kill but is very lazy. Although Confucius very carefully to teach, but his poor grades, Confucius has repeatedly to persuade him, but he doesn't listen to, spirit Confucius compare him to a useless dead wood.
Later, kill to by his eloquence, rank the prince did not last long, however, together with others because of the crisis, be neat WangChu died. Confucius and to hear of the death of, very regrets ground say: "from the son that I understand that, upon feather can not to look to the measure of a man; and the slaughter to also tell me, not only by a man says to measure him."